Is less than 24 bits worth it?

How does jitter have an effect? I don't know how CD players are commonly configured, but, if I were designing it the serial bits would be loaded into a buffer register in whatever irregular timing they might arrive with from the spinning disc. (Actually a set of buffer registers, for a cache of values). Then the 16 bit word would be output parallel to the D/A, and converted on a clock mark. Only the conversion clock mark needs to be timed accurately.

I've heard it said that the state of the art advances by a little more than one bit per decade. Certainly right now more than 20 bits are lost in the noise floor.

As the others have said, a well-executed 16-bit player sounds better than a typical mass-produced 20-bit player, and usually by a wide margin.

It's just like with power amps: not all 100 wpc amps are equal, and there are lot of 50 wpc amps that sound far better than many 100 wpc amps with most speakers.

When the analog signal is finally created, both amplitude and phase inaccuracy create deleterious effects. Using 24 bit resolution, the last bit translates to a signal amplitude of about a 17 millionth of peak amplitude. You can get an "equivalent" effect if the exact timing of that 24 bit sample is off by mere nanoseconds (depending on the exact slope at the sample moment), which is nothing more than jitter. Jitter that can affect the difference in timing from one sample to the next is created by intrinsic oscillator noise in Phase Locked Loops (the thing that tracks and creates the internal clock) or by the very bit stream itself (a phenomenon called data dependent jitter). CDPs can be more successful than transport/DAC combos in addressing these effects. Both have a really tough job getting true 24 bit resolution.

You all went over my head with this one!

(ask a simple question).

easy e

Sorry Easy_e. Just trying to address Eldartford's question above...